// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_FACTORY_H_
#define CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_FACTORY_H_

#include <string>

#include "base/callback.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "content/common/content_export.h"
#include "media/base/audio_latency.h"
#include "media/base/output_device_info.h"

namespace media {
class AudioRendererSink;
class SwitchableAudioRendererSink;
class AudioCapturerSource;
}

namespace url {
class Origin;
}

namespace content {

// A factory for creating AudioRendererSinks and AudioCapturerSources. There is
// a global factory function that can be installed for the purposes of testing
// to provide specialized implementations.
// TODO(olka): rename it, probably split it into AudioRendererSinkFactory and
// AudioCapturerSourceFactory.
class CONTENT_EXPORT AudioDeviceFactory {
public:
    // Types of audio sources. Each source can have individual mixing and/or
    // latency requirements for output. The source is specified by the client when
    // requesting output sink from the factory, and the factory creates the output
    // sink basing on those requirements.
    enum SourceType {
        kSourceNone = 0,
        kSourceMediaElement,
        kSourceWebRtc,
        kSourceNonRtcAudioTrack,
        kSourceWebAudioInteractive,
        kSourceWebAudioBalanced,
        kSourceWebAudioPlayback,
        kSourceWebAudioExact,
        kSourceLast = kSourceWebAudioExact // Only used for validation of format.
    };

    // Maps the source type to the audio latency it requires.
    static media::AudioLatency::LatencyType GetSourceLatencyType(
        SourceType source);

    // Creates a sink for AudioRendererMixer.
    // |render_frame_id| refers to the RenderFrame containing the entity
    // producing the audio. If |session_id| is nonzero, it is used by the browser
    // to select the correct input device ID and its associated output device, if
    // it exists. If |session_id| is zero, |device_id| and |security_origin|
    // identify the output device to use.
    // If |session_id| is zero and |device_id| and |security_origin| are empty,
    // the default output device will be selected.
    static scoped_refptr<media::AudioRendererSink> NewAudioRendererMixerSink(
        int render_frame_id,
        int session_id,
        const std::string& device_id,
        const url::Origin& security_origin);

    // Creates an AudioRendererSink bound to an AudioOutputDevice.
    // Basing on |source_type| and build configuration, audio played out through
    // the sink goes to AOD directly or can be mixed with other audio before that.
    // TODO(olka): merge it with NewRestartableOutputDevice() as soon as
    // AudioOutputDevice is fixed to be restartable.
    static scoped_refptr<media::AudioRendererSink> NewAudioRendererSink(
        SourceType source_type,
        int render_frame_id,
        int session_id,
        const std::string& device_id,
        const url::Origin& security_origin);

    // Creates a SwitchableAudioRendererSink bound to an AudioOutputDevice
    // Basing on |source_type| and build configuration, audio played out through
    // the sink goes to AOD directly or can be mixed with other audio before that.
    static scoped_refptr<media::SwitchableAudioRendererSink>
    NewSwitchableAudioRendererSink(SourceType source_type,
        int render_frame_id,
        int session_id,
        const std::string& device_id,
        const url::Origin& security_origin);

    // A helper to get device info in the absence of AudioOutputDevice.
    // Must be called on renderer thread only.
    static media::OutputDeviceInfo GetOutputDeviceInfo(
        int render_frame_id,
        int session_id,
        const std::string& device_id,
        const url::Origin& security_origin);

    // Creates an AudioCapturerSource using the currently registered factory.
    // |render_frame_id| refers to the RenderFrame containing the entity
    // consuming the audio.
    static scoped_refptr<media::AudioCapturerSource> NewAudioCapturerSource(
        int render_frame_id);

protected:
    AudioDeviceFactory();
    virtual ~AudioDeviceFactory();

    // You can derive from this class and specify an implementation for these
    // functions to provide alternate audio device implementations.
    // If the return value of either of these function is NULL, we fall back
    // on the default implementation.

    // Creates a final sink in the rendering pipeline, which represents the actual
    // output device.
    virtual scoped_refptr<media::AudioRendererSink> CreateFinalAudioRendererSink(
        int render_frame_id,
        int sesssion_id,
        const std::string& device_id,
        const url::Origin& security_origin)
        = 0;

    virtual scoped_refptr<media::AudioRendererSink> CreateAudioRendererSink(
        SourceType source_type,
        int render_frame_id,
        int sesssion_id,
        const std::string& device_id,
        const url::Origin& security_origin)
        = 0;

    virtual scoped_refptr<media::SwitchableAudioRendererSink>
    CreateSwitchableAudioRendererSink(SourceType source_type,
        int render_frame_id,
        int sesssion_id,
        const std::string& device_id,
        const url::Origin& security_origin)
        = 0;

    virtual scoped_refptr<media::AudioCapturerSource> CreateAudioCapturerSource(
        int render_frame_id)
        = 0;

private:
    // The current globally registered factory. This is NULL when we should
    // create the default AudioRendererSinks.
    static AudioDeviceFactory* factory_;

    static scoped_refptr<media::AudioRendererSink> NewFinalAudioRendererSink(
        int render_frame_id,
        int session_id,
        const std::string& device_id,
        const url::Origin& security_origin);

    DISALLOW_COPY_AND_ASSIGN(AudioDeviceFactory);
};

} // namespace content

#endif // CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_FACTORY_H_
